- Macro-nutrients: Carbohydrates, proteins & fats
- carbohydrates & fats provide energy
- proteins used as building blocks
- Micro-nutrients: vitamins and minerals
- When water removed from plants, mass is just macro-nutrients
- foraging → agriculture → population ↑
- Health advocates & advertisers promote diets based on these requirements
- plants can satisfy most of these resource needs
Complex Carbohydrates from Plants
- Commonly grouped into sugars and starches
- mono-, di- & polysaccharides (# of sugar units)
- Glucose & fructose (mono-) broken down in cellular respiration
- corn syrup = high fructose
- fructose common in fruit
- Sucrose (di-) commonly found in table sugar
- sugarcane and sugar beet
- Starches (poly-) are main storage form in plants
- seeds, fruits, tubers
- major staple crops and underground crops
Fiber in the Human Diet
- Fiber, a polysaccharides, is largely not digestible
- derived from plant sources
- Cellulose, lignin, pectin are components of cell walls
- humans lack enzymes to break them down
- Bacteria in intestines ferment soluble fibers!
- stabilizes blood glucose
- reduce cholesterol
- reduces cancer risks
Plant-Based Proteins
- 20 types of amino acids assembled into proteins
- regulate a variety of body functions
- proteins broken down by enzymes and transported through blood
- Dietary proteins need to provide 9 of 20 amino acids
- essential amino acids (9) not created or stored
- Plant-based proteins are ‘incomplete’
- do not contain all 9
- varied plant diet needed
- Traditional people of Mexico eat corn and beans
Gluten and Celiac Disease
Fats and Cholesterol from Plants
- Some fats (lipids) are necessary in human diets
- vital functions and heart health
- Food lipids are mostly fats and oils
- Human body cannot synthesis all fatty acids
- linoleic, linolenic & arachidonic acids
- all available in vegetable oils
- 1 tsp of corn oil supply each
- Vegetable oils are mostly unsaturated fats
- olive, peanut, corn, soybean, etc,
- unsaturated fats generally considered healthier
Micro-Nutrients from Plants
- Vitamins (organic) play a role as co-enzymes
- required for enzyme function
- Vitamin A (vision pigments) from yellow, orange and dark green vegetables and fruits
- beta-carotene
- Vitamin C (collagen synthesis)
- not produced or stored in body
- fruits and vegetables
Micro-Nutrients from Plants
- Minerals (inorganic) components of complex molecules
- at least 18 minerals needed
- Iron deficiency is common in women and children
- only 10% of dietary iron absorbed
- Leafy greens, grains, legumes and dried fruits
- Iron from animal = heme; from plants = non-heme
- heme gives blood its red color
- some plants, like legumes, contain heme.
Plant-Based Diets
- Vegetarian diets are shown to provide healthy benefits
- fewer chronic diseases
- blood cholesterol tracks animals fats
- high fiber reduces diabetes risk
- Plant-based diets must be aware of deficiencies
- iron, Vitamin B & D, calcium
- complementary plants for amino acids
The Staple Crops (Wheat, Maize & Rice)
Grass Family Most Important to Humans
- Edible grains of cultivated grasses basic food of human civilization
- wheat, core, rice
- barely, oats, millet & rye
- Sugar cane, a grass, world largest crop product
- 26 million hectares in 90 countries
- Dry fruits from the grass family are ‘grains’
- seed is mostly endosperm = starch
- refined into white flour, corn starch & white rice
- fruit wall + seed coat = bran fiber
- Wheat, Maize & Rice (refined + whole) provide 50% of human calories consumed
Wheat: The Staff of Life
- Wheat ‘spikes’ are densely packed with grains
- primarily grown in cool temperature zones
- wild species found in Fertile Crescent
- Einkorn wheat one of first cultivated species
- domesticate from is ‘non-shattering’
- hybridized with ‘goat grass’ to create ‘emmer wheat’
- ‘emmer wheat’ crossed with another ‘goat grass’
- diploid → tetraploid → hexaploid
- Currently 1,000s of wheat cultivars
- tolerance to climate
- amount of gluten
- protein content in endosperm
Corn: Indian Maize
- Summer annual, moderate temp and rain
- now: breed for diverse environments
- requires nutrient-rich soil
- today: hybrid corn w/ many large kernels
- Unknown to arriving Europeans
- most types cultivated by Native Americas
- poorly adapted for natural environment (husks)
- ‘Popcorn’ one of the most primitive varieties
- hard kernels, ‘hard’ starch around ‘soft’ starch
- burst and swell when heated
- avoids processing
Rice: Food for Billions
- Rice feeds more than any other crop
2 billion people
- 1,000’s of varieties
- Originated from wild ancestor in flooded tropical lowlands
- current: breed to grow any where
- Large annual grass with air chambers in stems
- air diffusion: stomata → roots
- Rice mostly cultivated into flooded fields
- aquatic fern, Azolla, provides nitrogen
- fields drained to harvest